Zinc phthalocyanine as a heterogeneous catalyst for efficient H2 generation from NaBH4 methanolysis

Abstract

Phthalocyanines have been extensively studied for their role in photodynamic therapy, sensors, optoelectronic devices etc.; however, their use as catalysts for hydrogen generation (HG) has remained a relatively unexplored area in scientific literature. This study is the first investigation into the catalytic potential of zinc phthalocyanine (ZnPc) complex in hydrogen production via methanolysis reaction of sodium borohydride (NaBH4). The kinetic performance of the ZnPc catalyst was evaluated based on catalyst amount, NaBH4 concentration, temperature, and reusability. The ZnPc-catalyzed NaBH4 methanolysis completed in 5.7 min, with a hydrogen generation rate of 8993 mLmin-1gcat-1—comparable to or better than many similar catalysts—and an activation energy of 28.47 kJ/mol. The catalyst exhibited remarkable reusability with no significant loss in catalytic activity when used for the three-cycle reaction. Additionally, the ZnPc-catalyzed NaBH4 methanolysis mechanism was also examined, revealing that –OH, –O–, and –N=N– groups play key roles in its notable HG efficiency. Overall, this study presents ZnPc as a promising catalyst for HG and emphasizes its catalytic efficiency and application potential in sustainable energy technologies .